Greater Greater Washington

Posts about California

Transit


Musk's Hyperloop math doesn't add up

On Monday, entrepreneur Elon Musk announced plans to build a design for a super-fast tube train connecting Los Angeles and San Francisco. He believes his plan will obviate the need for the California High-Speed Rail. Unfortunately, his math doesn't add up.


Photo by the author.

The "Hyperloop" would be a pair of tubes stretching from Los Angeles to the Bay Area. Pods within these tubes would travel at up to 760 mph, making the trip between California's largest metro areas in 35 minutes. Musk says he became motivated to invent this technology because he grew disenchanted with the California High-Speed Rail project's expense ($53 billion in 2013 dollars) and sloth (it will travel at an average of 168 mph).

Musk claims the Hyperloop system could be built for just $6 billion, 10% of the cost of HSR. Some are wondering if this is a serious proposal or a ploy intended to derail the California High-Speed Rail project. Evidence seems to point to the latter. After all, the guy proposing this revolution in transit owns a car company.

The Hyperloop concept has gotten a lot of press over the past few days. It seems to have inspired the masses like an idea out of Popular Mechanics. And it may very well be possible to build a system much like this one. Perhaps one day in my lifetime, people will be taking Hyperloops all over the nation.


Hyperloop concept drawings. All images from Musk's proposal.

Let's set aside for the moment any discussion of the technical feasibility of this project. The Hyperloop may very well be something that we have the skills and know-how to build. It may even be desirable in some corridors. But the technological concept is only part of what Musk has proposed.

Musk suggests that for less than 10% of the cost of building the long-planned high-speed rail line between Los Angeles and San Francisco, we can invent and build an entirely new technology. But the Hyperloop doesn't actually make it to downtown LA or downtown San Francisco. It also has a maximum passenger capacity of just 10% of the HSR line. And it bypasses all of the intermediate population centers in central California that HSR will serve.

If it sounds too good to be true, you should probably double-check the math. And the math surrounding the Hyperloop definitely has problems.

Unrealistic promises?

According to Musk, pods would depart LA and San Francisco every 30 seconds during peak periods. Each pod can carry 28 passengers. That means that under the maximum throughput, the Hyperloop is capable of carrying 3,360 passengers each hour in each direction.

For context, a freeway lane can carry 2,000 cars per hour. A subway running at 3 minute headways (like the WMATA Red Line) can carry 36,000 passengers per hour. The California High Speed Rail, which this project is supposed to replace, will have a capacity of 12,000 passengers per hour.

That means that Musk's proposal can carry only 20-25% of the passengers of the California High-Speed Rail under ideal circumstances. But are those ideal circumstances reasonable? Probably not.

The Hyperloop pods will travel at up to 760 miles per hour, just under the speed of sound, with pods traveling about 30 seconds apart in the tube. They will have a maximum deceleration of 0.5 gs, which is equivalent to 10.9 mph per second. At that rate of braking, it will take a pod 68.4 seconds to come to a full stop.

That's a pretty significant issue because safe vehicle operation means never getting closer to the vehicle ahead than the distance it will take you to stop. If pod A were to experience a catastrophic air-skid failure, crash into the tube wall, and disintegrate, pod B, 30 seconds back, would not be able to stop short of the wreckage. In fact, pod C would also likely hit the wreckage of pods A and B.

That means that the minimum separation between pods is probably closer to 80 seconds or more. Not a big deal. It still means 45 departures per hour. But that's only 1,260 passengers per hour in capacity. That's 10% of what the California High-Speed Rail can carry.

With a capacity of 1,260 passengers per tube, that means that the Hyperloop would need 10 tubes in each direction (not 1) to move the same number of passengers as the proposed high-speed line. And that would push the cost up by 10, which is actually more than the cost of the HSR.

Limitations

The maximum throughput of a transit line equals the throughput of the segment with the least capacity. Simply put, if we have a 2-track railway that has a long single-track segment, the whole line is limited by that section.

The Hyperloop will have chokepoints, too. Because the tubes will be kept at a near-vacuum, each station will have an airlock that trains pass through. Every time a pod arrives, it has to decelerate and stop. Then the airlock will have to close, pressurize, and open again. Then the pod has to clear the airlock. Then the airlock can close, depressurize, and then reopen.


A Hyperloop pod at a station.

All of that has to happen in less than 30 seconds (if Musk is to be believed) or 80 seconds if vehicles are kept a safe distance apart.

Meanwhile, Musk says that each station can have 3 pods on the platform at once. If pods arrive every 30 seconds, then passengers and baggage have to get off within 60 seconds. One arthritic passenger or a guy who goes back for the iPhone he left behind, and pods start backing up in the tube.

So clearly, Musk needs to rethink headways. The 30-second headway isn't feasible, meaning that his capacity will be significantly lower than he claims.

Maybe he can resolve that by using larger pods. But of course, a larger pod will weigh more. And that will probably mean using stronger steel for the tubes, which means that the cost will go up.

Apples to oranges

The California High-Speed Rail will whisk passengers from Los Angeles Union Station to the Transbay Terminal in downtown San Francisco in 2 hours and 48 minutes. That's too slow for Musk, and he says the Hyperloop can get you from Los Angeles to San Francisco in 35 minutes.


Proposed Hyperloop route. The line would stop short of both Los Angeles and San Francisco.

But the Hyperloop won't start in Los Angeles, and it won't end in San Francisco. Instead, it's proposed to start in Sylmar, 38 minutes north of Los Angeles Union Station aboard the Metrolink commuter train. That means it takes longer to get to the Hyperloop from downtown LA than it would take to go to San Francisco.

It's unclear where the Hyperloop would end. Some maps show the line crossing the San Francisco Bay either on or adjacent to the Bay Bridge. But his cost projections don't mention the expense of crossing the bay. Other maps show a terminal south of Oakland. So either his Bay Area station will be in the East Bay, requiring a transfer to BART to reach San Francisco, or he's lowballing the cost of the project. The 11-year long effort to rebuild the eastern span of the Bay Bridge has cost $6.3 billion, so another crossing won't be cheap.

Of course, there's nothing technically infeasible about extending the Hyperloop into downtown LA or San Francisco. But it would significantly increase the costs of the project. The California High-Speed Rail's sections in the San Joaquin Valley are also extremely cheap. If the HSR started in Sylmar and ended in Oakland, it would be significantly cheaper, too. While the cost of getting all the way downtown is already factored into the HSR project, it's not part of the Hyperloop proposal.

Conclusions

Musk's proposal won't actually get riders to the downtowns of Los Angeles or San Francisco. It can only carry around 10% of the capacity of the California High-Speed Rail. Additionally, it will bypass other population centers, like Bakersfield, Fresno, and San Jose.

Building a truly workable Hyperloop, if it's feasible at all, will be significantly more expensive than Musk claims. It might even be more expensive than the California HSR project. And Musk's proposal leaves a lot of questions unanswered.


The Hyperloop would run atop an elevated structure.

How did he come to his construction cost estimate in the first place? Musk argues that the Hyperloop is cheaper than HSR because it's elevated, saving on the cost of building at grade and reducing local opposition. But bridges are far more expensive than building tracks at grade. And just because the footprint is limited to a big pylon every 100 feet doesn't mean that the environmental impact analysis process will be any easier or that the public will be any more receptive.

Other issues, like seismic stability, are simply glossed over. He claims that by elevating the Hyperloop tracks, they will be more stable than ground-running HSR. Clearly he's unfamiliar with the Cypress Street Viaduct. That's one reason that the California High-Speed Rail Authority insists on crossing all faults at grade.

Musk also claims that his giant steel tube will be okay with the only expansion joints at the Los Angeles and San Francisco ends. They'll just be really big. That's a significant engineering issue that cannot simply be ignored, at least not if Musk is in any way serious about this proposal.

Realistically, the Hyperloop is just hype. The concept might be technically feasible. But Mr. Musk's proposal will cost a lot more and do a lot less than he claims it will. And clearly, it won't replace the high-speed rail project he hates so much. But it might just sell some Teslas.

Transit


LA's Orange Line shows the way for Montgomery BRT

The Institute for Transportation and Development Policy isn't so sure about many of the proposed Montgomery County Bus Rapid Transit lines, because of the county's spread-out, suburban character. But I took a trip on Los Angeles' first BRT line, which shows how BRT could indeed transform suburban commute patterns.


Boarding an Orange Line bus at Reseda. All photos by the author.

Built in 2005 and extended earlier this summer, the Orange Line runs between North Hollywood, Warner Center and Chatsworth in the San Fernando Valley. It's a suburban area with over 1.7 million people, known for wide boulevards, tract houses and shopping malls that gave rise to the infamous "Valley Girl."

Like Montgomery County, it has not one but several "downtowns." And like the Valley, Montgomery County has become more diverse, with more younger, immigrant or low-income residents who depend on transit, but also a growing interest in alternatives to driving among more well-heeled residents.

Why does the Orange Line work? It goes where people want to go, it's frequent, and it connects to the subway, major bus routes, and commuter rail. But more importantly, it gives riders a fast, pleasant experience that rivals driving in a place known for its car culture.

Orange Line Platform, North Hollywood
Passengers board a bus at North Hollywood Station.

The Orange Line includes many of the same features as Montgomery's BRT proposal, giving it the feel of a train. For instance, the stations are more substantial than normal bus shelters, with ticket machines, maps and benches, and signs saying when the next bus is coming. They have distinctive canopies that provide shade while giving the line a unique visual identity.

The buses are long and sleek, with big windows that make the inside feel bright and airy. They're actually the same buses the Los Angeles Metro uses elsewhere, though with a different paint scheme. Passengers pay by tapping a smart card at the station, and when the bus arrives, they can get on or off using any door, as they would on a train. I never had to wait more than 5 minutes for buses to arrive when I rode the Orange Line around 2pm, though they were still packed.

What makes the Orange Line really effective, however, is that buses have their own special lanes for the entire 18-mile route, the result of using a former rail line and a wide boulevard. There are also special sensors that turn stoplights green when buses approach so they don't have to stop. This allows buses to reach speeds of up to 55 miles an hour, cutting commutes across the Valley nearly in half and making it as fast, if not faster, than driving. The busway is lushly landscaped, while a popular bike and foot path runs alongside it. The result is a commute that's not only convenient, but very pleasant.

Bike Path + Transitway, Between Woodman + Valley College Stations
A bike path next to the Orange Line busway.

As a result, ridership has almost doubled from 16,000 people each weekday in 2005 to 31,000 today. That's the same number of riders planners anticipate will use certain BRT lines in Montgomery. By comparison, the busiest conventional bus routes in both the Valley and Montgomery County carry just 10,000 riders per weekday.

One rider told me, completely unprompted, how much he liked the Orange Line. "Thank God for Metro," he said. "I'm glad they have all these buses and trains now. Back in the day, we didn't have none of this and you had to have a car."

Unfortunately, Montgomery County's BRT plan wouldn't always give buses their own lanes, even in congested areas like downtown Bethesda and downtown Silver Spring. Buses would be stuck in traffic with everyone else, making it a lousy alternative to the car.

Busway on Chandler Boulevard, Laurel Canyon Station
Orange Line buses run in their own lanes on busy Chandler Boulevard.

That said, at $25 million per mile, the Orange Line cost nearly twice as much to build as Montgomery's BRT is expected to, and we can't afford to make that kind of investment in places where it's not warranted. Some areas in the 160-mile system envisioned by the county's Transit Task Force might be better suited for smaller improvements, like the Metro Rapid buses in Los Angeles that inspired MetroExtra service here.

However, in areas where transit use is already high, we should go all out to encourage more of it. The Orange Line didn't require taking away lanes from cars, but we will have to in Montgomery County to get the same quality of service. It won't be easy, but it can and should be done.

It's no surprise that some officials, like County Councilmember Nancy Floreen, are skeptical of Montgomery's BRT plan. "This is suburbia," she told the Washington Examiner. "To assume that everyone is going to switch to a nice, snazzy looking bus is not particularly realistic."

And she's right: no one's going to ride the bus, especially if we don't make it worthwhile. The Orange Line shows us that in the right places, you can get suburban riders on the bus if you give them a fast, frequent, and pleasant experience. We'd do well to follow their example.

Check out this slideshow of the Orange Line.

Development


Mission Meridian Village shows suburban density done right

It's commonly accepted that we should build up around public transit, but how can you do it in a way that respects existing neighborhoods? Yesterday, I visited Mission Meridian Village in South Pasadena, California, a project that shows how to do just that.


Mission Meridian Village. All photos by the author.

Designed by New Urbanist architects Moule & Polyzoides and developed in a public-private partnership between the city and Creative Housing Associates, Mission Meridian Village opened in 2003 across from the then-new South Pasadena Gold Line station, which connects to downtown Los Angeles.

The project is located next just off of Mission Street, a quaint shopping district like Old Town Takoma Park where light-rail trains glide past coffeehouses and bakeries. Closer to Mission Street is a larger commercial building with shops and loft apartments, while behind it are a mix of apartments, townhomes, and single-family homes that seem to blend into the surrounding neighborhood of humble Craftsman bungalows. An underground parking garage, with spaces for residents and commuters, runs under the entire site.

Duplex + Crosswalk
A duplex at Mission Meridian Village.

From the street, you see a row of duplexes, each of which has a similar scale and uses the same materials as existing homes. The only hint that these aren't ordinary houses are the little paths that lead into 3 lush courtyards, where you'll find entrances to the other homes.

Inside the Courtyard
Inside one of the courtyards.

All of this happens on 1.65 acres, about a fourth bigger than a football field. With about 67 homes, Mission Meridian Village has a density of 40 homes per acre, but it doesn't feel crowded. Each house has its own private outdoor space, be it a porch, a patio or a balcony. Meanwhile, residents have eagerly embraced the shared courtyards. Chairs and tables spill out from patios into the space, while kids' toys lie on the ground, waiting for the next game.

Mission Meridian Village is a great example of how to provide much-needed housing in a way that gives residents open space and a feeling of community. It's also an example for how to build better suburban neighborhoods where a car isn't mandatory. Most importantly, however, it's an example of how to add to a community while respecting what's already there.

Check out this slideshow of Mission Meridian Village.

Support Us

How can our region be greater?

DC Maryland Virginia Arlington Alexandria Montgomery Prince George's Fairfax Charles Prince William Loudoun Howard Anne Arundel Frederick Tysons Corner Baltimore Falls Church Fairfax City
CC BY-NC